CHAPTER IV 



DISCOMYCETES 



THE term Discomycetes is applied to those groups in which the fruit is 

 more or less cup-shaped (fig. 51), with the hymenium fully exposed at 

 maturity, and to their immediate allies. The ascocarp is surrounded by a 

 peridium or sheath of closely interwoven hyphae which is closed at first and 

 later is pushed apart by the paraphyses, so that at last it forms the outer 



Fig. 



Otidea aurantia Mass.; 

 nat. size. 



ipotheci, Fig. 52. Lachnea stercorea (Pers.) Gill.; ascocarp in 

 longitudinal section showing young asci and para- 

 physes, x 160. a. sheath; b. paraphyses; c. ascus; 

 a. ascogenous hyphae ; e. oogonium ;/. stalk of archicarp. 



wall of the cup (fig. 52). The lower part of the cup is filled by the hypo- 

 thecium, a tangle of hyphae, some vegetative, some ascogenous. These 

 give rise to the sub-hymenial layer where the paraphyses have their origin 

 and where the young asci are developed. The asci and paraphyses grow up 

 together and rise to the surface of the ascocarp forming the hymenium or 

 fertile disc which is spread over the interior of the cup. The asci are more 

 or less cylindrical and parallel one to another and to the paraphyses (fig. 53). 

 They open either by a lid (fig. 55) or by the ejection of a plug (fig. 54). 

 They arise in succession so that large numbers may be produced in a single 

 ascocarp. If the hypothecium is well developed the apothecial cup is full 

 and the hymenium lies across the brim like the skin on a bowl of custard ; 

 if the development of the hypothecium is slight the hymenium spreads over 



